Click to enlarge image.  

The Refuge Gateway continues to develop a dramatic landscape transformation. Earthworks and seeding have restored over 41 acres of forest, prairie, and wetland habitat. In Summer 2012, the installation of native seed and the planting of over 300 native trees at the Gateway site have assisted in the completion of vital restoration of high quality coastal wildlife habitat.

Click to enlarge image. 

Learn more about Native Seed & Tree Plantings at the Refuge Gateway. 

Through the historical development of the Refuge Gateway site for industrial purposes during the 1940s–1960s, river bottom and wetlands were filled to support a number of manufacturing operations. At the time of closure of the plant in 1990, the site was relatively flat, with a significant drop at a 90 degree angle to the Detroit River. The site master plan called for the restoration of a more natural shoreline at the Refuge Gateway. A coastal wetland and habitat restoration plan was then prepared in 2010 by a team of expert scientists, engineers, designers, and representatives from regulatory agencies, accounting for the site environmental constraints.

The project team, with concurrence from state and federal regulatory agency staff, agreed to limit
excavation above the old river bottom and a layer of clay and topsoil were installed creating a cap over the contaminated material. The project team modified the design plans to construct a coastal wetland shelf along the entire Detroit River shoreline and riparian buffer habitat at the southeastern corner of the site.

In 2011, shoreline restoration began with the removal of fill from the land at the southeast corner of the property. To avoid exposing residual contamination and creating a direct hydrologic pathway to the Detroit River, and to comply with regulatory agency cleanup standards and shoreline restoration permits, the shoreline restoration design had to be modified consistent with an adaptive management philosophy. In an area that has lost an estimated 97% of historical coastal wetland habitat, this shoreline restoration project would represent a regional net gain of nearly three acres of this threatened habitat.

For more information about the Shoreline Restoration work done at the Refuge Gateway site, download Transformation of an Industrial Brownfield into an Ecological Transformation of an Industrial Brownfield into an Ecological Buffer for Michigan’s Only Ramsar Wetland of International Importance.

Click to enlarge image. 

Prior to industrial development, storm water from a small watershed in the city of Trenton was transported to the Detroit River through a concrete underground pipe. As a result, the piped Monguagon Drain passed through the Refuge Gateway site into Humbug Marsh as a natural creek.

In an effort to showcase sustainable practices incorporated into the Refuge Gateway Master Plan, the Monguagon Creek was unearthed from an underground pipe and daylighted in 2009. The project included constructing a storm water treatment basin and an emergent wetland as a two-step process of naturally treating urban storm water before entering the Detroit River.

Today, the drain is daylighted and naturally filtered before releasing into its historical route through Humbug Marsh. The retention pond accomplishes settling of solids and the emergent wetland promotes nutrient uptake – the equivalent of a biological cleansing of the storm water being emitted from the drain. A pump installed in the wetland allows for the movement of water from the constructed wetland into the adjacent Monguagon Delta of Humbug Marsh.

Moving water into Humbug Marsh can be used as a management tool for decreasing the density of invasive Phragmites in the Monguagon Delta after Phragmites has been treated and removed, thereby promoting greater native species diversity from the existing seed bank. Additionally, the delta provides more than three acres of established emergent wetland for additional storm water treatment. Other project benefits included wildlife habitat creation and opportunities for hands-on environmental education and natural resource interpretation.

For more information about the Monguagon Creek project, email Allison Krueger, Landscape Designer for the Detroit River International Wildlife Refuge Alliance.

Click to enlarge image.